1. Field of the Invention
The present invention relates to a technique of analyzing the imaging position of each of multiple frames constituting an image, for example, a moving image, captured by a traveling vehicle.
2. Background Art
Various applications have been proposed for images captured with a video camera mounted on a vehicle. For example, information on these captured images is utilized for generation of electronic map data, which provides a three-dimensional map reproducing the town as a three-dimensional image based on computer graphics. The technique disclosed in Japanese Patent Laid-Open No. H07-37065 (Patent Document 1) combines multiple frame images captured with a video camera and generates one composite image covering a wide area. The generated composite image may be utilized for monitoring, for example, the status of the railway track or the status of the power cable.
For such applications of the images captured with the video camera, it is essential to accurately detect the imaging position of each frame image, for example, as latitude/longitude coordinates. The techniques disclosed in Japanese Patent Publication No. 2687645 (Patent Document 2) and in Japanese Patent Laid-Open No. 07-71973 (Patent Document 3) identifies the position of the vehicle in its moving direction by utilizing a known distance, for example, the number of intermittent white lines provided as a road lane marking or the number of posts of a guardrail. The combined use of a GPS (global positioning system), a gyroscope, or another positioning sensor for the detection of the vehicle position has also been proposed.